The invention resides in the mechanical field, and more particularly in the medical engineering field. It relates to pumps being equipped with pump rotors and having a pump housing, the interior of which accommodates the pump rotor. In particular in the medical engineering field, however, generally also in any other technical fields of application, pumps are known, which may be radially compressed in that both the rotor and the pump housing may be deformed in order to reduce the diameter, and which are expandable at the site after transport, in order to adjust to the measurements required for an optimized function. Further, in particular in the medical engineering field, such pumps are known, which may be compressed such that the same may be inserted into a blood vessel into the body of a patient, and may be expanded there, in order to support or independently enable the blood transport via the operation of the pump.
In order to ensure a reliable collapsibility and expandability, a plurality of technical problems must be solved.
For example, U.S. Pat. No. 7,393,181 B2 describes a collapsible pump rotor, in which conveyor vanes are disposed in rows on a hub, and may be retractable on the same.
A pump rotor is known from U.S. Pat. No. 7,841,976 B2, which may be inserted into the expandable part of a cannula, in order to be operated there after the respective cannula part has expanded. For this purpose the rotor is driven via a shaft extending through the cannula. The pump formed in this manner may be advanced through a blood vessel all the way into a heart chamber, and operated at that location.
U.S. Pat. No. 7,927,068 B2 also describes a pump having a rotor, which has a hub and retractable and tiltable conveyor vanes. The conveyor vanes are pushed into the position suitable for the pump operation during the operation of the rotation by means of the fluid counter pressure created.
An intravascular pump having a collapsible and expandable housing is known from DE 100 59 714 01, which has a mesh. This housing may accommodate a rotor, and may be inserted into a blood vessel by means of an insertion lock.
The prior art state above generally deals with the problems of compressing a pump having a rotor and a pump housing radially sufficient so that the same may, for example, be inserted into a blood vessel of a patient, and may be expanded after insertion. At a later time the respective pump should also be collapsible again in order to be able to be removed. In the compressing and expansion process both the rotor and the housing are commonly deformed correspondingly. A special challenge is found in the requirement of minimizing the pump gap, i.e. the intermediate space between the rotor, more specifically the radial external ends of the conveyor vanes, and the internal housing wall of the pump housing during operation, in order to optimize the pump operation, in particular the effectiveness and the compressing of the pump. The pump gap must be very small and, in particular, must be held as constant as possible in order to prevent any overflow at the radial external ends of the conveyor elements of a rotor, on the other hand the conveyor elements or other elements of the rotor should not contact the interior wall of the pump housing, if at all possible, in order not to generate any unnecessary friction losses or abrasion wear at the commonly high rotational speeds of more than 10,000 rotations per minute.